Fig. 1

Rapid, repeated drops in temperature (upward spikes in the dotted line) were accompanied by concomitant increases in mortality, especially in control broods. Predicted values (relative risk of nest failure, i.e., daily mortality relative to the mean) and corresponding standard errors from the best-supported Cox proportional hazard model (see Table 2a) are plotted against date. The grey bands represent the standard error of the predicted values for the risk of nest failure (left y-axis). The dotted blue line shows the daily maximum temperature (°C) and corresponds to the right y-axis. To facilitate interpretation, the scale on the right y-axis was reversed